The 24th annual Contact conference was held in April 2008 at NASA Ames, in northern California's Silicon Valley. About 150 people participated, with many excellent speakers, a concert piano recital, and of course, the high school level COTI HI first-contact encounter.
My photos are here.
Scroll on through. Related web links, if available, are below the images.
The Oroville Mercury-Register ran a great article about this year's COTI HI participants.
(Currently you have to log on at their site, then search for it. Try using 'NASA' as a keyword.)
Official Contact home page.